Meade 102 ED triplet objective clean,

[johnyjf]

I have a Meade 102 ED triplet the rear surface of the objective needs a clean. Although the focuser assembly unscrews easily this does not give adequate access for a proper clean and I would like to remove the lens cell. Trying to unscrew it would seem to require far more force than unscrewing the focuser and I am wary of applying too much pressure for fear of causing permanent damage. Has anyone removed the lens cell from one of these instruments and if so what's the secret please?
John

[Lady Fraktor]

I have not removed a Meade lens cell before, if it is taking more than reasonable force to move it I would suspect it is either glued in place or there are still holding screws hiding somewhere.
Is this a series 5000 refractor or something different?
I may find something scrounging through my older HD

[AstroBee]

Just how dirty is the rear element of a triplet going to get unless it was stored standing up on the objective end with no cap on the focuser end? Many people see a few specks of dust, thinking it needs cleaning when likely you are to make things much worse in an attempt at cleaning it.

[johnyjf]

Firstly, Yes it is a 5000 series refractor, sorry should have said so in original post. Secondly, its nothing quite as trivial as a few specs of dust, I'm well aware of the benefits of leaving well enough alone. This problem was caused by an insect getting into the scope, dying and attempting to decompose on the back of the glass. The decomposing insect deposits organic acid on the glass that can damage the coatings and even the surface of the glass itself if left. I removed the insect OK but the cloth I used left a few smears. I have had trouble clearing them no matter which combination of cloth and cleaning fluid I use. A large part of the problem is that I can't get at it evenly. Removing the focuser, dead easy but the cell doesn't want to unscrew. I just wondered if anyone knew of a way to remove it. If glued in place the removal is not going to be a trivial task. I can't see any hidden screws but I'll have another look over the weekend. I don't want to disassemble the lens elements from the front, accurate collimation won't be easy, I've never done it on a refractor before and don't think an ED triplet is a good place to start. Thanks for your inputs.

[AstroBee]

Maybe this post over on CN will help.
https://www.cloudynights.com/topic/6166 ... -to-clean/

[Lady Fraktor]

If this is a doublet it can be collimated with simple tools at home, triplets are a different matter though.

One thing that I use is a wooden dowel about 1 metre long. I have a very soft 6mm camel hair brush taped to it so I can safely brush the inner lens of the refractor.
I also use a 13mm poly tube (again taped to a wooden dowel) taped to a vacumn hose to suck up any dust/ debris. The hose is long enough to get within 10-15mm of the lens.

If you are careful with what you do you can use this approach if needed.
I will see if I can find the best way to remove the cell but it will be later in the day (06:40 here)

[Richard]

From my experience most triplets (3 lenses ) are locked in place to prevent them being moved and require special tools to take them apart and refit them, so be very carefull , if you have not done it before then dont try , Google is NOT your friend here , its probably the hardest telescope to sort out if its out
I would get a pro to clean it
I often wodered that even closed , when one changes eyepieces etc something may fly in , well it did for me on a Mak , probably because I was looking at the moon so was quite bright inside , I wanted a lower eyepiece and by my error took one out and left the scope without and eyepiece in for like 2 min when I looked for a better one , then I looked again with a 32mm their was a tiny thing flying around
Leave any scope open at your perill

[johnyjf]

Once again thanks for the input. The cloth on a stick approach sounds close to what I have already tried without much success. I never intended to take the lens cell apart, just to remove it as an entity and clean the rear element surface. I am taking it to a professional technician next Thursday morning to look at it and decide if he will take it on.
Clear Skies!

[Lady Fraktor]

I spent some time looking through the Meade information that I have.
Do you know how many 102 ED refractors Meade has made? Doublets, triplets and no way to identify them unless you have a picture to go by! Even the series 5000 usually reference the 80mm and 127mm, I found one reference to a 102mm triplet but then the image shown was of 2 different telescopes and both images were mislabeled anyways

Hopefully you can get this sorted right away.

[Lady Fraktor]

Do you have a name/ business you could pass along for this person that can align triplets?
A rare contact in USA.
Such people are even getting harder to find in Europe.

[Mike Q]

http://www.company7.com/products.html
http://astronomy-shoppe.com/?page_id=35

Maybe these guys can help

[Lady Fraktor]

I would not count on that, C7 normally only help clients that have purchased from them in the past.

[johnyjf]

Once again thanks for all the helpful comments. I know of no one who can collimate triplets in the USA, I'd be hard pushed to find anyone who can in the UK. I took the telescope to Optrep in Selsey UK. The technician is really a binocular specialist and is well aware of the difficulty in collimating triplets and is not prepared to try. He was confident he can clean the rear objective front and rear without the need to meddle with the lens elements. I will report back when he has completed the work. Once again thanks for the advice, will be back soon with a positive report I hope.

[johnyjf]

Hello again, The professional technician has tried to remove the lens cell from the tube without success, suspect it's glued into place. I will pick the scope up Wednesday and will have to do some more thinking. I guess cleaning the rear element will mean disassembling the triplet after which it will probably need collimation, not a cheap business assuming I can find someone capable of doing it this side of China or Taiwan. Meanwhile I'll contact Meade UK, maybe they can offer some help.

[Lady Fraktor]

There is no longer a Meade UK, that used to be Bresser Telescopes (UK & EU) who are now the EU Vixen dealer now that Orion owns Meade.

There was a business in USA named Subbarth? or something close to that who would do the occasional triplet. There is I believe a business called New England Telescopes/ Optics that does collimation of triplets.
One other location but in Canada is Markainian Fine Optics in Vancouver, British Columbia. Call/ email and see if they can help you. They may be the cheapest.

If you decide to send it to EU I would try Wellinform, most higher end retailers here use them. APM Telescopes uses them for repairs/ testing.

[DeanD]

I suspect the business referred to is Suddarth Optics. https://suddarthoptical.com
They have a great reputation for binos, but i am not sure about refractors.

Good luck with the Meade!

[Lady Fraktor]

They are a binocular repair but have done triplets in the past since they use the same equipment to align their optics.
I knew I was close with the name but not 100%
The New England location is sometimes used by Stellarvue to inspect older triplets now that they are concentrating on their SVX line.

This is quickly becoming a lost art, I wish I had the room & €€€ to set up a good zygo inferometer.
A bit of advertising and I could semi-retire!

[johnyjf]

Hello Again, lots of information above for which I thanks the posters. I have reclaimed the scope and after some communication with a UK Meade official dealer decided to try a little gentle heat on the lens cell, this did not succeed in loosening it. In desperation I decided to try a home made solution to cleaning the rear element. I took a 25 mm plastic water pipe and inserted a soft 35 mm suction pad into the end. I then took 3 optical quality microfibre cleaning cloths and wrapped them over the suction pads to form a thick layer. I clamped the lot in place with a very tight cable tie. I then wet the cloths thoroughly with Zeiss optical fluid and carefully and thoroughly wiped the lens back paying special attention to the outside edge where the original smears were located. The result, perfection, all the smears disappeared and with a light clean to the front of the glass normal service has been resumed. That is to say the sky is clouded over and looks like staying that way for a few days yet. Thaanks for all the help!

[John Baars]

Great!!
So it seems that common sense combined with precaution and caution wins out!
Very well done! My compliments.